<script>
  let names = Object.getOwnPropertyNames(window);

  function filterOut(names, props) {
    let set = new Set();
    props.forEach(o => set.add(o));
    return names.filter(e => !set.has(e));
  }

  // ECMA 262
  {
    let js=new Set();
    let objects=[]
  }

  console.log(names)
</script>